I literally just discovered that the trac "milestone" pages can be
edited.

This seems like a much better place to put the 1.1, 1.2, and 1.3
release series wiki pages. So I moved all the content and updated the
links on the front wiki page. Each "1.x" milestone is now a top-level
view of the entire series with links to individual milestone pages for
details about that specific release. For example:

Release Managers / Gatekeepers:
- the pages are editable just like other wiki pages, so nothing
changes there
- when you edit the milestone page, I note that there's a handy
"Retarget associated open tickets to milestone [X]" option for moving
all leftover tickets to the next milestone